1. Field of the Invention
The present invention relates to an image processing method and device for the same by which image data is quantized.
2. Related Background Art
At present, an Adaptive Discrete Cosine Transform ADCT (Adaptivraphic Expert Group) system is intended to be standardized as a compression system of a multi-value image data by JPEG (Joint Photographic Expert Group).
Also, it is contemplated to use the ADCT system in the field of a color image communication, in particular, in the field of a color facsimile.
Nevertheless, the above ADCT system has been studied to be applied to an image having the relatively small number of pixels such as an image on a CRT.
Therefore, the application of the ADCT system, as it is, to a field such as the color facsimile requiring a high resolution gives rise to a new problem. More specifically, when the ADCT system is employed for the color facsimile, as it is, a deterioration of image quality such as shade off, dislocation and spread of color is caused in the field of fine lines of characters, graphics and the like.
Further, when data compressed by the ADCT system is compared with data prior to compression, density is not preserved and thus image quality is deteriorated.